Well fracturing manifold apparatus

ABSTRACT

A fracturing system can include a fracturing manifold coupled to a plurality of fracturing trees. The fracturing manifold may include adjustment joints that enable adjustment of the length of the fracturing manifold. The fracturing manifold can also include pivot joints that allow angular displacement of portions of the fracturing manifold with respect to other portions. The adjustment and pivot joints can accommodate spacing and elevation differences between the fracturing trees.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the presently describedembodiments. This discussion is believed to be helpful in providing thereader with background information to facilitate a better understandingof the various aspects of the present embodiments. Accordingly, itshould be understood that these statements are to be read in this light,and not as admissions of prior art.

In order to meet consumer and industrial demand for natural resources,companies often invest significant amounts of time and money insearching for and extracting oil, natural gas, and other subterraneanresources from the earth. Particularly, once a desired subterraneanresource is discovered, drilling and production systems are oftenemployed to access and extract the resource. These systems may belocated onshore or offshore depending on the location of a desiredresource. Further, such systems generally include a wellhead assemblythrough which the resource is extracted. These wellhead assemblies mayinclude a wide variety of components, such as various casings, valves,fluid conduits, and the like, that control drilling or extractionoperations.

Additionally, such wellhead assemblies may use a fracturing tree andother components to facilitate a fracturing process and enhanceproduction from a well. As will be appreciated, resources such as oiland natural gas are generally extracted from fissures or other cavitiesformed in various subterranean rock formations or strata. To facilitateextraction of such resources, a well may be subjected to a fracturingprocess that creates one or more man-made fractures in a rock formation.This facilitates, for example, coupling of pre-existing fissures andcavities, allowing oil, gas, or the like to flow into the wellbore. Suchfracturing processes typically include injecting a fracturingfluid—which is often a mixture or slurry including sand and water—intothe well to increase the well's pressure and form the man-madefractures.

A fracturing manifold may provide fracturing fluid to one or morefracturing trees. Conventionally, the fracturing manifold is set backfrom the fracturing trees and valves of the manifold are tied to eachfracturing tree by manifold output lines (e.g., “frac iron” or pipes)dedicated to routing fracturing fluid to that tree. To allow fracturingoperations, the ends of each manifold output line are connected betweenthe fracturing manifold and a respective fracturing tree. Further, themanifold output lines may be secured (e.g., via straps) to inhibitmovement of the manifold output lines if the lines become disconnectedfrom the manifold or their fracturing trees.

SUMMARY

Certain aspects of some embodiments disclosed herein are set forthbelow. It should be understood that these aspects are presented merelyto provide the reader with a brief summary of certain forms theinvention might take and that these aspects are not intended to limitthe scope of the invention. Indeed, the invention may encompass avariety of aspects that may not be set forth below.

Embodiments of the present disclosure generally relate to a fracturingmanifold coupled to one or more fracturing trees. Fracturing fluid canbe routed from the fracturing manifold to the one or more fracturingtrees and into wells. In one embodiment, the fracturing manifoldincludes an adjustment joint and a pivot joint. The adjustment and pivotjoints facilitate connection of the manifold and allow the manifold toaccommodate variations in well spacing and elevation.

Various refinements of the features noted above may exist in relation tovarious aspects of the present embodiments. Further features may also beincorporated in these various aspects as well. These refinements andadditional features may exist individually or in any combination. Forinstance, various features discussed below in relation to one or more ofthe illustrated embodiments may be incorporated into any of theabove-described aspects of the present disclosure alone or in anycombination. Again, the brief summary presented above is intended onlyto familiarize the reader with certain aspects and contexts of someembodiments without limitation to the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of certain embodimentswill become better understood when the following detailed description isread with reference to the accompanying drawings in which likecharacters represent like parts throughout the drawings, wherein:

FIG. 1 generally depicts a fracturing system with an integral fracturingmanifold in accordance with an embodiment of the present disclosure;

FIG. 2 is a diagram of the fracturing system of FIG. 1 with the integralfracturing manifold coupled to multiple fracturing trees in accordancewith an embodiment of the present disclosure;

FIG. 3 is a perspective view of certain components of a fracturingsystem, including the integral fracturing manifold, fracturing trees,and adjustment joints, in accordance with an embodiment of the presentdisclosure;

FIG. 4 is an elevational view of the fracturing system componentsdepicted in FIG. 3;

FIG. 5 is a top plan view of the fracturing system components depictedin FIGS. 3 and 4;

FIG. 6 is a perspective view of an adjustment joint as depicted in FIGS.3-5 in accordance with an embodiment of the present disclosure;

FIG. 7 is a cross-section of the adjustment joint of FIG. 6 inaccordance with an embodiment of the present disclosure; and

FIG. 8 generally depicts the adjustment joint of FIGS. 6 and 7 followingadjustment to increase its length in accordance with an embodiment ofthe present disclosure.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present disclosure will bedescribed below. In an effort to provide a concise description of theseembodiments, all features of an actual implementation may not bedescribed in the specification. It should be appreciated that in thedevelopment of any such actual implementation, as in any engineering ordesign project, numerous implementation-specific decisions must be madeto achieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure.

When introducing elements of various embodiments, the articles “a,”“an,” “the,” and “said” are intended to mean that there are one or moreof the elements. The terms “comprising,” “including,” and “having” areintended to be inclusive and mean that there may be additional elementsother than the listed elements. Moreover, any use of “top,” “bottom,”“above,” “below,” other directional terms, and variations of these termsis made for convenience, but does not require any particular orientationof the components.

Turning now to the present figures, an example of a fracturing system 10with an integral fracturing manifold is provided in FIGS. 1 and 2 inaccordance with one embodiment. The fracturing system 10 facilitatesextraction of natural resources (e.g., oil or natural gas) from a well12 via one or more wellbores 14 and wellheads 16. Particularly, byinjecting a fracturing fluid into the well 12, the fracturing system 10increases the number or size of fractures in a rock formation or stratato enhance recovery of natural resources present in the formation. Thefracturing fluid may, for example, include a sand-laden slurry (e.g., apound of sand per gallon of water), drilling fluid, high concentrationsof hydrochloric acid (e.g., up to mole percentage of eighteen percent),fresh water, saline water, or produced water. In the presentlyillustrated embodiment, the well 12 is a surface well accessed byequipment of wellhead 16 installed at surface level (i.e., on ground18). But it will be appreciated that natural resources may be extractedfrom other wells, such as platform or subsea wells.

The fracturing system 10 includes various components to control the flowof fracturing fluids into the well 12. For instance, the fracturingsystem 10 includes one or more fracturing trees 20 and a fracturingmanifold 22. In at least one embodiment described in greater detailbelow with respect to FIGS. 3-5, the fracturing manifold 22 isintegrated with the fracturing trees 20 (i.e., coupled without usingseparate output lines or frac iron to connect the fracturing manifold 22and the fracturing trees 20). The fracturing trees 20 include at leastone valve that controls flow of the fracturing fluid into the wellheads16 and, subsequently, into the well 12.

As depicted in FIG. 2, the fracturing manifold 22 is connected toprovide fracturing fluid to multiple fracturing trees 20 and wellheads16. But it is noted that the fracturing manifold 22 may instead becoupled to a single fracturing tree 20 in full accordance with thepresent techniques. Fracturing fluid from a supply 28 is provided to thefracturing manifold 22. In FIG. 1, a connector 30 receives fracturingfluid from the supply 28 through a conduit or fluid connection 32 (e.g.,pipes or hoses) and then transmits the fluid to the fracturing manifold22 by way of a subterranean conduit or fluid connection 34 (e.g.,pipes). In one embodiment, the fracturing fluid supply 28 is provided byone or more trucks that deliver the fracturing fluid, connect to theconnector 30, and pump the fluid into the fracturing manifold 22 via theconnector 30 and connections 32 and 34. In another embodiment, thefracturing fluid supply 28 is in the form of a reservoir from whichfluid may be pumped into the fracturing manifold 22. But any othersuitable sources of fracturing fluid and manners for transmitting suchfluid to the fracturing manifold may instead be used.

A portion 40 of the fracturing system 10 is illustrated in FIGS. 3-5 inaccordance with one embodiment. In the depicted embodiment, the portion40 includes several fracturing trees 20 joined to both wellheads 16 andthe fracturing manifold 22. The manifold 22 includes a conduit 42 (alsoreferred to as a main or shared trunk line) that routes fracturing fluidto the fracturing trees 20. The conduit 42, in turn, includes sectionsof pipe 44, adjustment joints 46, connection blocks 48, and pivot joints56.

The components of the conduit 42 may have any bore diameter, material,and thickness appropriate for the intended application. For instance, inone fracturing application the conduit 42 includes a seven-inch bore andmaterial (e.g., steel) with a thickness sufficient to sustain continuousdelivery of fluid at high pressures (e.g., 15,000 psi). In anotherembodiment, the conduit 42 includes a three-inch bore.

In the presently depicted embodiment, the manifold 22 is an integralfracturing manifold. That is, rather than more conventional fracturingmanifolds that are constructed to be installed (e.g., on the ground or askid) apart and separate a distance from fracturing trees on wellheadsand then connected to each fracturing tree with one or more manifoldoutput lines (e.g., frac iron) specifically assigned to that fracturingtree, the manifold 22 is positioned right up to the fracturing treeswithout intervening frac iron, pipes, or fracturing heads. In such anintegral fracturing manifold embodiment, the installed fracturing trees20 and wellheads 16 provide stability, allow the omission of manifoldskids, and consequently reduce leveling and settling issues related tosuch manifold skids.

In the depicted portion of the manifold 22, the connection blocks 48themselves are coupled to valves 50 (e.g., gate valves) of thefracturing trees 20 to provide fracturing fluid to the fracturing trees20. As will be appreciated, an operator may fracture a well 12 byopening the valves 50 of a particular fracturing tree 20 and allowingfracturing fluid to pass through that fracturing tree 20 into theassociated well 12. The fracturing trees 20 and wellheads 16 maystructurally support the manifold 22 by bearing some or all of itsweight. But other support structures may also or instead be used to bearthe weight of the manifold 22.

Further, by installing the fracturing manifold 22 on the fracturingtrees 20 themselves, the overall footprint for fracturing operations isreduced, as is the number of components (and potential leak or failurepoints) in the system. For instance, rather than including valves on themanifold to control fluid output to the fracturing trees, the directconnection to the valves 50 of the fracturing trees 20 allow theintegrated manifold 22 to omit separate valves on the manifold itself.Still further, in some instances (e.g., in extremely cold conditions)the fracturing trees 20 may be at least partially enclosed intemperature-controlled structures and the integration of the manifold 22allow the manifold 22 to also benefit from the temperature-controlledstructures. Accordingly, the integration of the manifold 22 with thefracturing trees 20 may reduce construction, installation, andoperational costs associated with a fracturing operation.

The embodiment depicted in FIGS. 3-5 includes two valves 50 connectingeach fracturing tree 20 to the fracturing manifold 22. But any othersuitable number of valves may instead be used to control flow offracturing fluid to the fracturing trees 20. Additionally, although thefracturing trees 20 are provided in the form of horizontal fracturingtrees in the present embodiment, other embodiments may include differentstyles of fracturing trees (e.g., vertical trees). It is also noted thatwhile three fracturing trees 20 are depicted in FIGS. 3-5, the integralfracturing manifold may be coupled to any number of fracturing trees inother embodiments. For instance, additional pipes 44, adjustment joints46, connection blocks 48, or pivot joints 56 may be connected at ends 52or 54 of the illustrated portion of the manifold 22 to transmitfracturing fluid to additional fracturing trees.

In a production field, wellheads may be unevenly spaced from one anotherand installed at different elevations. But in the depicted portion 40,the inclusion of adjustment joints 46 and pivot joints 56 in theintegral fracturing manifold 22 facilitates installation of the manifold22 on the fracturing trees 20 and allows accommodation of somevariations in well spacing and elevation. Particularly, the adjustmentjoints 46 may be extended or retracted to adjust the length of themanifold 22 (and accommodate variations in distance between fracturingtrees 20) and the pivot joints 56 (e.g., ball joints) allow portions ofthe manifold 22 to be positioned at angles with respect to one another(to accommodate one or both of elevation differences or non-linearity ofspacing between fracturing trees 20).

By way of example, an elevational view of the portion 40 of thefracturing system 10 is provided in FIG. 4. In this illustration, thecenter wellhead 16 and fracturing tree 20 are at a higher elevation thanthose to the right and left, such as would occur if the center wellhead16 was installed on a slight rise in the ground compared to the adjacentwellheads 16. The pivot joints 56 allow portions of the conduit 42(e.g., the pipes 44 and adjustment joints 46 installed between two pivotjoints 56) to be positioned at angles 60 to accommodate elevationdifferences 62. FIG. 4 generally depicts the left and right wellheads 16(and fracturing trees 20) having similar elevation differences 62 withrespect to the center wellhead 16 (and fracturing tree 20). But it willbe appreciated that the respective elevation differences 62 between theouter wellheads 16 and the center wellhead 16, as well as thepositioning angles 60 to compensate for such elevation differences 62,may vary from one another.

Similarly, the pivot joints 56 may also or instead accommodate lateralspacing deviations between adjacent wells as depicted in the top planview of the portion 40 in FIG. 5. Particularly, the pivot joints 56 ofthe depicted embodiment also allow portions of the conduit 42 (e.g., thesame pipes 44 and adjustment joints 46 noted above with respect to FIG.4) to be positioned at angles 66 to accommodate lateral spacingdifferences 68 between wellheads 16 and fracturing trees 20. As above,the lateral spacing differences 68 need not be identical and may bedifferent from one another depending on the position of the wellheads 16and the fracturing trees 20.

The pivot joints 56 may be said to allow portions of the conduit 42 tobe rotated in each of two perpendicular planes (e.g., vertical andhorizontal with reference to the ground) to allow two degrees oftranslational freedom (e.g., up-and-down and left-and-right) inpositioning a portion of the manifold 22. The amount of freedom providedmay vary depending on the design of the fracturing system 10 and thedimensions of the pivot joints 56 and the other components of themanifold 22. In one embodiment, the pivot joints 56 may allow angularrotation of up to fifteen degrees from the normal (i.e., the angles 60and 66 in their respective planes may vary between negative and positivefifteen degrees, inclusive).

The adjustment joints 46 provide a third degree of translational freedom(e.g., back-and-forth) by allowing variation in a dimension (e.g.,length) of the adjustment joints 46 and, consequently, in the length ofthe conduit 42 between adjacent connection blocks 48. An adjustmentjoint 46 in accordance with one embodiment is illustrated in greaterdetail in FIGS. 6-8. But it is noted that other adjustment joints orconnectors may instead be used in full accordance with the presenttechnique.

In the depicted embodiment, the adjustment joint 46 includes a bodyhaving a first portion 72 and a second portion 74. The body portions 72and 74 are configured to move with respect to one another to vary adimension of the adjustment joint 46 and accommodate spacing andelevation differences between fracturing trees 20, as described above.The adjustment joint 46 includes fluid ports 76 and 78 to transmit fluidthrough the adjustment joint 46. In addition to the fluid port 76, thesecond body portion 74 includes a set of studs 80 and nuts 82 forconnecting the adjustment joint 46 to another component (e.g., a flangedpipe 44). Similarly, the first body portion 72 includes through holes 84arranged in a flange 86 about the fluid port 78 for coupling to anothercomponent (e.g., another flanged pipe 44 via additional studs and nuts).The first body portion 72 includes an additional set of through holes 88positioned radially outward from the through holes 84. The through holes88 are aligned with mating holes 90 in a flange 92 of the second bodyportion 74, and the first and second body portions 72 and 74 are securedto one another with studs 94 (through the holes 88 and 90) and nuts 96.

As depicted in FIGS. 7 and 8, a bore 98 extends through the adjustmentjoint 46 between the fluid ports 76 and 78. The bore 98 may have adiameter similar or identical to that of the components coupled to thefluid ports 76 and 78, such as seven inches in one embodiment (thoughother diameters may be used for the bore 98, as well as for othercomponents). The adjustment joint 46 includes an adjustment collar 100that may be rotated on threads 104 by a user to translate the collar 100with respect to the body portion 72 or 74 on which the collar isthreaded (i.e., first body portion 72 in FIGS. 7 and 8). Movement of theadjustment collar 100 allows adjustment of the length of the adjustmentjoint 46 and the distance between fluid ports 76 and 78. Particularly,as illustrated in FIG. 8, nuts 96 may be loosened on the studs 94 andthe adjustable collar 100 may be moved along the first body portion 72to lengthen the adjustment joint 46. In this manner, the length (or whatmay instead be considered the height) of the adjustment joint 46 may bevaried to aid in aligning and coupling the fracturing manifold 22 to thefracturing trees 20. The adjustment joint 46, or alternative adjustmentjoints in other embodiments, may be constructed to allow for any desiredamount of variation in dimension. For instance, the adjustment jointsmay be constructed to allow dimensional variation (e.g., lengthening) ofseven inches in one embodiment, of twelve inches in another embodiment,and of eighteen inches in still another embodiment.

The adjustment joint 46 also includes various sealing elements toinhibit fluid leakage. For instance, as depicted, the adjustment joint46 includes sealing elements 102, 106, 108, 110, and 112. The sealingelements are formed of any suitable material, such as an elastomer ormetal. In one embodiment, the seals 106 and 108 include CANH™ sealsavailable from Cameron International Corporation of Houston, Tex. Also,in one embodiment movement of the collar 100 pre-loads or energizes oneor more of the seals of the adjustment joint 46.

While the aspects of the present disclosure may be susceptible tovarious modifications and alternative forms, specific embodiments havebeen shown by way of example in the drawings and have been described indetail herein. But it should be understood that the invention is notintended to be limited to the particular forms disclosed. Rather, theinvention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by thefollowing appended claims.

The invention claimed is:
 1. A fracturing system, comprising: a firstwell fracturing tree; a second well fracturing tree; a first connectionblock; and a second connection block; wherein the first connection blockis coupled in fluid communication with the first well fracturing treevia two valves so as to provide a straight flow path to route fracturingfluid from the first connection block into the first well fracturingtree through the two valves, the second connection block is coupled influid communication with the second well fracturing tree via twoadditional valves so as to provide a straight flow path to routefracturing fluid from the second connection block into the second wellfracturing tree through the two additional valves, and the firstconnection block is in fluid communication with the second connectionblock through a portion of a manifold trunk line.
 2. The system of claim1, wherein the first well fracturing tree and the second well fracturingtree bear at least a portion of the weight of the manifold trunk line.3. The system of claim 1, wherein the two valves and the two additionalvalves are gate valves.
 4. The system of claim 1, wherein the portion ofthe manifold trunk line includes a plurality of pipe sections.
 5. Thesystem of claim 1, wherein the portion of the manifold trunk lineincludes an adjustment joint that enables variation in the length of theportion of the manifold trunk line.
 6. The system of claim 1, whereinthe portion of the manifold trunk line includes a pivot joint.